Inhibition of protein kinase C translocation from cytosol to membrane by chelerythrine.

Protein kinase C (PKC) is regarded as an important signal in cellular responses. Chelerythrine, the alkaloid in Zanthoxylum simulans, was recently introduced as a specific blocker of PKC phosphorylation. The present study demonstrated an inhibitory effect of chelerythrine on the translocation of PKC from cytosol to membrane using Western blotting analysis. An increase of PKC translocation from cytosol to the membrane was observed in isolated ileal synaptosomes incubated with phorbol 12-myristate 13-acetate (PMA) to reach the plateau at 30 min later. Pretreatment with chelerythrine for 20 min attenuated this action of PMA in a concentration-dependent manner and the inhibition of PKC alpha translocation was similar to that of PKC beta. An inhibitory effect of chelerythrine on the translocation of PKC is considered in addition to the inhibition of PKC phosphorylation.